Moisture is known to condense on skylights, refrigerator/freezer doors, vehicle windows, lighting systems, and other glass-inclusive products. Condensation buildup on skylights detracts from the aesthetic appeal of the lite. Similarly, condensation buildup on refrigerator/freezer doors in supermarkets or the like sometimes makes it difficult for shoppers to quickly and easily pinpoint the products that they are looking for. Condensation buildup on automobiles often is an annoyance in the morning, as a driver oftentimes must scrape frost or ice and/or actuate the vehicle's defroster and/or windshield wipers to make it safer to drive. Moisture and fog on the windshield oftentimes presents a similar annoyance, although they may also pose potentially more significant safety hazards as a driver traverses hilly areas, as sudden temperature drops occur, etc.
Condensation buildup on lighting systems (e.g., billboards, etc.) also can occur. In fact, given the widespread adoption of Solid-State Lighting (SSL) solutions and the fact that their light sources (e.g., LEDs) typically do not generate infrared (IR) heat (unlike some High-Intensity Discharge (HID), Incandescent, and Halogen light source technologies) when generating light, the condensation problem can be more severe, e.g., because of visibility and safety concerns. It is believed that no SSL-based solution has been able to be used successfully on a commercial scale in applications where the lighting fixture is directly exposed and susceptible (close to ground level) to ice and snow build-up, and/or where full light output is critical for safety (e.g., airport runways, walkways, stairs, etc.), for example.
Thus, it will be appreciated there is a need in the art for improved lighting systems (e.g., SSL lighting systems) that do not suffer from these and/or other condensation issues.
One aspect of certain example embodiments of this invention relates to a heatable glass lens solution that provides localized heating to remove condensation (e.g., snow, ice, etc.) build-up thereon, that otherwise could reduce the associated lighting system's light output and efficiency.
Another aspect of certain example embodiments of this invention relates to a monolithic tempered coated glass solution that allows the glass lens to be rapidly and uniformly heated in a SSL fixture while also achieving high light output efficiency.
Certain example embodiments include a high transmittance conductive coating (e.g., greater than about 87% on clear float glass), that optionally incorporate a visual antireflective (AR) coating on the opposite side of the monolithic glass lens to further enhance light transmission (e.g., for another 4% point visible light transmission gain).
In certain example embodiments of this invention, a lens for a lighting system is provided. A glass substrate supports antireflective and transparent coatings on first and second major surfaces thereof, respectively. At least one bus bar is in electrical communication with the conductive coating, with the at least one bus bar being configured to convey voltage to the conductive coating from an external power source to, in turn, cause the conductive coating to heat up. The antireflective and transparent coatings are sputtered coatings. The substrate is heat treated together with the antireflective and transparent coatings thereon.
According to certain example embodiments, a lighting system may include one or more solid state lights (e.g., LEDs, OLEDs, PLEDs, Plasma Emitting Discharge, etc., in an array or other format). The lenses described herein may, for example, be interposed between the one or more solid state lights and a viewer of the lighting system. A power source operable to drive the conductive coating of the lens at a power density of 1-6 W/in2 is provided.
In certain example embodiments of this invention, a lighting system including one or more solid state lights is provided. A lens is spaced apart from the one or more solid state lights. The lens includes: a first glass substrate supporting a sputter-deposited antireflective coating on a major surface thereof and a second glass substrate supporting a sputter-deposited conductive coating on a major surface thereof. The first and second substrates are laminated to one another such that coated surfaces thereof face away from one another. The first substrate with the antireflective coating thereon and/or the second with the conductive coating thereon is/are heat treated.
In certain example embodiments of this invention, a method of making a heatable lens for a lighting system is provided. A multilayer antireflective coating is sputter deposited on a first major surface of a glass substrate. A multilayer conductive coating is sputter deposited on a second major surface of the glass substrate, with the first and second major surfaces being opposite one another. The glass substrate is heat treated with the multilayer antireflective and conductive coatings thereon. At least one bus bar is disposed on the glass substrate such that the at least one bus bar is in electrical communication with the conductive coating so as to heat the substrate when voltage is provided from an external power source.
According to certain example embodiments, a method of making a lighting system is provided. The methods of making the lenses described herein may be performed. A solid state light source is provided. The lens is provided in spaced apart relation to the light source. The at least one bus bar of the lens is connected to an external power source.
The features, aspects, advantages, and example embodiments described herein may be combined to realize yet further embodiments.